Pressure responsive switch actuator



I. J. REED PRESSURE RESPONSIVE SWITCH ACTUATOR Filed March '28, 1947 Ira. J :REECL.

A no rney:

July 5, 1949.

Patented July 5, 1949 UNITED STATES PATENT OFFICE PRESSURE RESPONSIVE SWITCH ACTUATOR Ira J. Reed, Kokomo, Ind.

Application March 28, 1947, Serial No. 737,989

2 Claims. (01. 200-52) This invention relates to a mechanical actuating means for electric switches and more particularly to a pressure responsive switch actuator for bins, hoppers and other containers.

While the invention is adapted for use in hoppers, bins and containers generally, it has been illustrated and will be described in conjunction with a hopper or bin'of a coal stoker to function in response to the lowering of the level of the fuel of the hopper or bin beyond a predetermined point for shutting off the motor which drives the stoker worm by the actuation of an electric switch and for simultaneously energizing an audible or visual signal, connected to said switch, for indicating a low supplyof fuel in the hopper or bin.

More particularly, it is an object of the present invention to provide a switch actuator of extremely simple construction, which is reliable and durable in operation, simple and inexpensive to manufacture, which may be quickly and easily installed on hoppers, bins or containers already in use, and which will function automatically to energize or de-energize an electric circuit without resetting.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, illustrating a preferred embodiment and application thereof, and wherein:

Figure l is a side elevational view of a stoker hopper or bin shown equipped with the invention;

Figure 2 is a cross sectional view thereof taken substantially along a plane as indicated by the line 2--2 of Figure 1;

Figure 3 is an enlarged transverse sectional view through the switch actuator, taken substantially along a plane as indicated by the line 3--3 of Figure l;

Figure 4 is a cross sectional view taken substantially along a plane as indicated by the line 4-4 of Figure 3, and

Figure 5 is a plan view of the switch actuator with a portion of the cover shown broken away.

Referring more specifically to the drawing, the pressure responsive switch actuator, designated generally 8, is shown mounted in one of the inclined side walls of a hopper or bin 1 forming a part of a fuel stoker 8, and as best illustrated in Figure 2, the switch actuator 6 is shown disposed adjacent the bottom or discharge part of the hopper and in which the feed worm 9 of the stoker 8 is disposed.

In order to mount the switch actuator 6 in the hopper I, it is only necessary to drill a single opening in the inclined wall thereof, and as best seen in Figure 3. The switch actuator includes a substantially flat mounting plate H which is provided with an opening I 2 which is preferably centrally disposed relatively thereto for receiving one end of a tubular member l3 which is anchored in the opening l2 and which projects from one side thereof through the hopper opening It. The tube I3, if desired, may be formed integral with the mounting plate H or may be fixedly or detachably secured thereto and is externally threaded to receive a lock nut l4 which bears against the outer side of the hopper 1, around the opening It for detachably mounting the plate II on the inner side of the hopper and over the opening Ill thereof.

A pressure responsive actuator plate I5 is attached adjacent one end thereof to the mounting plate II in a manner to permit a limited pivotal movement of the plate l5 relatively to the plate The mounting of the plate IS on the plate I I is preferably accomplished by means of a pair of shoulder rivets f6 which loosely engage the plate I5 to permit the free end thereof to rock toward and away from the plate Likewise, as best seen in Figures 3 and 5, the pressure responsive plate I! is pivotally mounted on the mounting plate H at its upper end and adjacent material such as rubber, canvas, leather or the like and the edge portion thereof is disposed beneath the edge 01' a mounting plate II' to be clamped between said mounting plate and the hopper wall by tightening of the lock nut It so as to position the central portion of the cover l1 loosely over the pressure responsive plate I5 so that it will not prevent it from swinging outwardly to its position of Figure 3.

A switch housing I8 is provided with an internally threaded angularly disposed nipple l9 which threadedly engages the outer end of the tube I3 and which is provided with a restricted inner end 20 to engage a retaining washer 2|, which is mounted in the outer end of the tube l3 and to retain said washer 2| so positioned. The washer 2| is provided with a restricted opening 22 for reciprocably receiving a plunger rod 23 having a head 24 at its outer end which is larger than the opening 22 for limiting the upward or inward movement of said plunger rod relatively to the tube l3. The plunger rod 23, adjacent its opposite, upper end is provided with a collar 25 which is fixed thereto and which slidably engages the bore of the tube I: to combine with the opening 22 for guiding the plunger rod 23 in its reciprocatory movement. An expansion coil spring 26 is contained within the tube I 3 and on the plunger rod 23 and has one end thereof seating against the retaining washer 2| and the opposite end bearing against the collar 25 for urging the plunger rod 23 upwardly and against the pressure responsive plate I5 for holding said plate in a projected position away from the mounting plate I I, as illustrated in Figure 3.

A conventional electric switch 21 is contained in the switch housing I8, said switch being of any conventional double throw type of ample capacity and having a sensitive snap action, such as the switch covered by U. S. Patent No. 1,960,020 and which is provided with an actuator arm 28 projecting therefrom and by means of which the switch 21 is actuated. The switch 21 is provided with three electrical connections including an electrical conductor 29 which is adapted to be connected to any suitable source of electric current and with two electrical conductors 30 and 3i, one of which is adapted to be connected to the electric motor, not shown, for driving the worm 9 and the other of which is adapted to be connected to an audible 'or visual signal, not shown, and which are alternately actuated by movement of the switch lever 28.

Figure 3 illustrates the position that the part of the switch actuator 6 will assume when the portion of the hopper or bin 1 in which said actuator is mounted, is otherwise empty. It will thus be seen that the spring 28 will hold the pressure responsive plate I5 away from the mounting plate I I and will also hold the head 24 away from the switch lever 28, in which position, the circuit to the electric motor, not shown, for driving the worm 9, will be broken to prevent operation of the stoker 8 and the circuit to the audible or visual. signal will be energized for indicating that the supply of fuel in the hopper 1 is substantially exhausted and that the stoker has been rendered inoperative.

When the hopper l is filled or substantially filled the weight of the fuel, not shown, contained therein will bear against the flexible cover I! to press it and the pressure responsive plate I5 against the mounting plate II causing the pressure responsive plate I5 to project the plunger 23 downwardly against the spring 28 so that the head 24 thereof will engage and rock the switch lever 28 for breaking the circuit to the electric indicator and for closing the circuit to the Stoker motor to permit the stoker to operate in a conventional manner. This circuit will be maintained until the supply of fuel falls below the lower end of the plate I5 at which time the spring 26 will expand to project the plunger rod 23 upwardly for returning the plate I 5 to its position of Figure 3, to thereby break the circuit to the stoker motor and energize the visual or audible warning device. This will cause the circuit to the motor to be opened before the bottom of the hopper is entirely empty, leaving sufficient fuel to maintain a seal in the worm housing.

Further, it will be readily apparent that the cover I! merely functions in combination with the plate II to form a collapsible housing for the pressure responsive plate I5 to prevent said plate from coming in contact with the fuel and to prevent fuel from lodging beneath the plate I5 and preventing correct operation thereof.

Various modifications and changes are contemplated and may obviously be resorted to, without departing from the spirit or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. A pressure responsive switch actuator comprising, in combination with an electric switch having an actuating lever, a mounting plate adapted to be disposed in a hopper, bin or container, an externally threaded tubular extension adapted to extend through an opening in a wall of said container and having one end extending through and detachably connected to the mounting plate, a flexible covering disposed loosely over the side of said mounting plate opposite to that from which the tubular extension projects and having a marginal portion disposed between said plate and said container wall, a lock nut on said tubular extension for engaging the outer side of said container wall for clamping said marginal portion of the flexible covering between the mounting plate and container wall, a pressure responsive plate pivotally mounted on the mounting plate and between it and said flexible covering, and a spring projected plunger slidabl disposed in said tubular extension and spring urged against said pressure responsive plate for urging it outwardly of the mounting plate, said flexible covering being adapted to be collapsed against the mounting plate by the pressure of the contents of the container for forcing said pressure plate inwardly or toward the mounting plate for retracting said plunger, and said plunger being constructed and arranged to engage and actuate the switch lever, when retracted.

2. A pressure responsive switch actuator comprising, in combination with an electric switch having an actuating lever, an actuator housing adapted to be disposed in a container and including a substantially rigid wall adapted to be disposed adjacent a wall of the container and an opposite collapsible wall, a tube having one end secured in said rigid wall and opening into said housing and projecting outwardly therefrom and adapted to extend through an opening in the container Wall, said tube being externally threaded, a lock nut on the threaded tube for engaging the outer side of the container wall for clamping the actuator housing to the inner side thereof, a pressure responsive plate pivotally mounted on the rigid wall of the housing and between said rigid wall and the collapsible wall, and a spring projected plunger slidably disposed in said tube and spring urged against the pressure responsive plate for urging it toward said collapsible housing wall, said collapsible housing wall being adapted to be collapsed against the rigid housing wall by the pressure of the contents of the container for forcing said pressure responsive plate against the rigid housing wall to retract the spring projected plunger, and said spring projected plunger having an end disposed to engage and actuate the switch lever when retracted.

IRA J. REED.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,892,084 Sprague Dec. 27, 1932 1,911,530 Raisch et al May 30, 1933 1,977,223 Carter Oct, 16, 1934 2,153,716 Kelly Apr. 11, 1939 

